A known image forming apparatus includes a developing device unit, and a belt unit and a drum unit that are disposed above the developing device unit. To prevent the developing device unit from interfering with the drum unit when the developing device unit is drawn, the image forming apparatus is configured to move the drum unit upward and downward in response to the opening and closing movements of an upper cover of the image forming apparatus. After the upper cover is opened to retract the drum unit upward, a front cover of the image forming apparatus is opened to withdraw the developing device unit.